U.S. patent number 4,913,683 [Application Number 07/215,077] was granted by the patent office on 1990-04-03 for infusion stent system.
This patent grant is currently assigned to Medical Engineering Corporation. Invention is credited to Franklin P. Gregory.
United States Patent |
4,913,683 |
Gregory |
April 3, 1990 |
Infusion stent system
Abstract
The infusion stent system includes a stent member having a
plurality of openings provided in the wall of the stent along the
entire length of the stent. An imperforate open ended guide tube
member used for installation and infusion of the stent accommodates
a core member that stiffens the guide tube member. The core member
is relatively moveable in the guide tube member to provide
selective flexibility at a proximal end of the guide tube member.
The stent is positioned in the renal cavity, the ureter and bladder
by being pushed along the guide tube member by a push catheter.
Fluid is infused through a proximal end of the guide tube member
when the core member is removed. The proximal end of the guide tube
member can be located at any selected position within the stent.
Thus fluid can be infused to any selected location in the stent by
positioning the proximal end of the guide tube member at a desired
location in the stent. Openings in the stent that are bypassed by
the guide tube member are not infused with fluid.
Inventors: |
Gregory; Franklin P. (Racine,
WI) |
Assignee: |
Medical Engineering Corporation
(Racine, WI)
|
Family
ID: |
22801546 |
Appl.
No.: |
07/215,077 |
Filed: |
July 5, 1988 |
Current U.S.
Class: |
604/8; 604/500;
604/528 |
Current CPC
Class: |
A61M
27/008 (20130101); A61M 2025/0063 (20130101) |
Current International
Class: |
A61M
25/00 (20060101); A61M 025/00 () |
Field of
Search: |
;604/8-10,34,43,281,282 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truluck; Dalton L.
Attorney, Agent or Firm: Krieger; Stuart E.
Claims
What is claimed is:
1. An infusion stent system comprising
a. a flexible stent member of a first predetermined length, said
stent member having a main body portion with a proximal end portion
and a distal end portion,
b. a hollow flexible guide tube member of a second predetermined
length greater than said first predetermined length, said guide
tube member being infusible with fluid and receivable in said stent
member such that said stent member and said guide tube member are
relatively slidable with respect to each other, said guide tube
member having a proximal end that is positionable in said stent
member at any selected location within said stent member, such that
when the proximal end of said guide tube member is at any said
selected location in said stent member infusion of fluid through
said guide tube member is directed outwardly of said guide tube
member at any said selected location in said stent member, said
guide tube member being removable from said stent member.
2. The infusion stent system as claimed in claim 1 wherein said
guide tube member is substantially imperforate.
3. The infusion stent system as claimed in claim 1 wherein said
guide tube member is formed of a fluorinated polymer.
4. The infusion stent system as claimed in claim 3 wherein said
guide tube member is formed with a wire reinforcement.
5. The infusion stent system as claimed in claim 1 including a
flexible core member of a third predetermined length greater than
said second predetermined length, said core member being sized for
slidable reception in said guide tube member, said core member
including insertion limiting means nonreceivable in said guide tube
member to limit insertion of said core member in said guide tube
member.
6. The infusion stent system as claimed in claim 5 wherein said
flexible core member has a proximal free end positionable in said
guide tube member at any selected location within said guide tube
member, said flexible core member being removable from said guide
tube member.
7. The infusion stent system as claimed in claim 6 wherein said
flexible core member has a terminal section of predetermined extent
up to the proximal free end of said core member and a first
substantially uniform cross section between said insertion limiting
means and said terminal section, said terminal section having a
reduced cross-section with respect to said first substantially
uniform cross-section.
8. The infusion stent system a claimed in claim 7 wherein the
proximal free end of said core member has an enlargement with a
cross-sectional magnitude that is greater than the cross-sectional
magnitude of said terminal section and approximately equivalent to
the cross-sectional magnitude of said first substantially uniform
cross-section.
9. The infusion stent system as claimed in claim 7 wherein the
terminal section of said flexible core member is tapered toward the
proximal free end of said core member to a minimum tapered
cross-section, the proximal free end of said core member having an
enlargement with a cross-sectional magnitude that is greater than
the cross-sectional magnitude of said minimum tapered cross-section
an approximately equivalent to the cross-sectional magnitude of
said first substantially uniform cross-section.
10. The infusion stent system as claimed in claim 5 wherein said
stent member has normally curved proximal and distal end portions,
and wherein the flexibility of said guide tube member and said core
member are selected such that said curved proximal and distal end
portions are substantially straightened when said stent member is
disposed on said guide tube member with said core member engaged in
said guide tube member, the flexibility of said guide tube member
permitting said normally curved proximal and distal end portions of
said stent member to re-form when said core member is disengaged
from the guide tube member at the area of disposition of said stent
member on said guide tube member.
11. The infusion stent system as claimed in claim 2 including a
hollow, tubular, flexible, push catheter member of a fourth
predetermined length, said fourth predetermined length being of
lesser magnitude than said third predetermined length, said push
catheter member being sized for slidable engagement on said guide
tube member and having a wall thickness that interferes with the
distal end portion of said stent member to permit said push
catheter to abut said distal end portion of said stent member such
that movement of said push catheter member against said stent
member causes said stent member to move along said guide tube
member.
12. The infusion stent system as claimed in claim 2 wherein said
stent member has a plurality of openings along the length thereof
such that when the proximal end of said guide tube member is at any
said selected location in said stent member infusion of fluid
through said guide tube member is directed outwardly of said stent
member through openings in said stent member beyond said selected
location.
13. The infusion stent system as claimed in claim 2 wherein said
stent member has a plurality of openings along the length thereof
and wherein the proximal end of said guide tube member is
positionable at the proximal end of said stent member to bypass
selected said openings in said stent member up to the proximal end
portion of said stent member and permit infusion of fluid outwardly
of said stent member substantially only at openings in the proximal
end portion of said stent member that are not bypassed by said
guide tube member.
14. The infusion stent system as claimed in claim 2 wherein said
stent member has a plurality of openings along the length thereof
and wherein the proximal end portion of said guide tube member is
positionable in said stent member intermediate said proximal and
distal end portions of said stent member to bypass openings in said
stent member up to the location of the proximal end portion of said
guide tube member and permit infusion of fluid outwardly of said
stent member substantially only at openings in said stent member
that are not bypassed by said guide tube member.
15. An infusion stent system comprising
a. a flexible hollow imperforate guide tube member having a
proximal end with an infusion opening;
b. a flexible hollow stent member slidable on said guide tube
member;
c. a flexible hollow push catheter member slidable on said guide
tube member for pushing said stent member along said guide tube
member to a predetermined position in the renal cavity, ureter and
bladder, said push catheter member being removeable from said guide
tube member, and
d. said hollow flexible guide tube member being moveable relative
to said stent member when said stent member is in said
predetermined position, such that the proximal end of said guide
tube member is positionable at selected predetermined locations in
said stent member to permit infusion of fluid outwardly of said
guide tube member at said selected predetermined locations in said
stent member.
16. The infusion stent system as claimed in claim 15 wherein said
stent member includes a plurality of perforations, the proximal end
of said guide tube member being positionable at said selected
predetermined locations in said stent member to bypass selected
perforations in said stent member and permit infusion of fluid
outwardly of said stent member substantially only at perforations
in said stent member that are not bypassed by said guide tube
member.
17. The infusion stent system as claimed in claim 15 further
including a flexible core member slidably engageable in said guide
tube member to selective positions within said guide tube member up
to the proximal end of said guide tube member.
18. The infusion stent system as claimed in claim 17 wherein said
core member has a terminal section and a main body section, said
terminal section having a lesser cross-sectional magnitude than the
main body section.
19. The infusion stent system as claimed in claim 18 wherein said
terminal section has a free end with an enlargement of greater
cross-sectional magnitude than said terminal section and lesser
cross-sectional magnitude than said main body section.
20. A method of infusing fluid in the renal cavity comprising
a. forming a flexible, hollow guide tube member with inlet and
outlet openings,
b. locating the guide tube member in the renal cavity, the ureter
and the bladder,
c. drawing a stent member onto the guide tube member,
d. pushing the stent member along the guide tube member with a push
catheter until the stent member is located in the renal cavity, the
ureter and the bladder;
e. moving the guide tube member relative to the stent member such
that the outlet opening of the guide tube member is at a
pre-selected location in the stent member, and
f. infusing fluid through the inlet opening of the guide tube
member for flow outwardly of the outlet opening of the guide tube
member at the preselected location in the stent member.
21. The method of claim 20 including perforating the stent member
along its entire length, and infusing fluid through the guide tube
member for flow outwardly of the stent member at perforations in
the stent member beyond the outlet opening of the guide tube
member.
22. The method of claim 21 wherein the renal cavity is infused by
locating the outlet opening of the guide tube member in a position
in the stent member that bypasses the perforations in the stent
member except the perforations that are proximal to the renal
cavity, and infusing fluid through the guide tube member for
passage through the stent member into the renal cavity.
23. The method of claim 21 wherein the ureter is infused by
locating the outlet opening of the guide tube member in a position
in the stent member that bypasses the perforations in the stent
member up to the ureter and infusing fluid through the guide tube
member for passage through the stent member into the ureter.
24. The method of claim 18 including inserting a non-tubular core
member into the guide tube member during location of the guide tube
member in the renal cavity, the ureter and the bladder, and
maintaining the core member in the guide tube member until the
stent member is also located in the renal cavity, the ureter and
the bladder.
Description
BACKGROUND OF THE INVENTION
This invention relates to ureteral stents, and more particularly to
a novel infusion stent system that permits infusion of fluid at any
selected location in the stent.
Ureteral stents have long been used for such purposes as draining
fluid from the renal pelvis to the bladder, and for providing
support to a collapsed or restricted ureter.
Ureteral stents may also be used in conjunction with extracorporeal
shock wave lithotropsy (ESWL), a procedure for pulverizing kidney
stones without surgery. During ESWL, a device known as a
lithotripter emits high frequency electrohydraulic waves that
destroy the kidney stones. The waves are administered to a patient
submerged in a bath of water. Electrodes are attached to brass disk
behind the patient and when the lithotripter is activated, up to
1500 electrohydraulic waves travel through the water to crush the
stone to infinitesimal fragments that the patient can then pass
naturally. The natural passing of the stone is facilitated with a
stent.
One known stent used in ESWL procedures, designated the Kwart
Retro-Inject Stent manufactured by Cook Urological of Spencer,
Ind., and identified by Model Nos. 003600 and 003700, includes a
system comprising a stent, a solid core wire guide, an inserter and
a release sleeve. The stent is normally coiled or looped at
opposite ends and includes perforations along the length of the
stent.
In using the Kwart Retro-Inject Stent Set, the wire guide is
positioned in the patient and the stent is pushed on the wire guide
into the renal cavity by the inserter. The inserter is pushed into
the stent a distance of approximately 5 mm thus forming a tubular
extension of the stent.
After the stent is positioned in the patient, the wire guide is
removed to allow the stent coils or loops to re-form in the renal
pelvis. Fluid is injected through the inserter and into the stent
during an ESWL procedure to disclose stones or stone fragments for
targeting. The stent can also be left in place for internal
drainage.
One of the problems with the Kwart Retro-Inject stent system is
that infusion of fluid through the inserter cannot be specifically
directed outwardly of the stent at any selected portion of the
stent. Fluid is injected into one end of the stent through the
inserter. The injected fluid traverses the stent exiting through
any or all of the openings in the stent.
Another known stent set manufactured by Cook Urological under the
designation Wegenke Exchange/Retrograde Ureteral Stent Set Model
No. 0046, is also unable to direct fluid to any selected part of
the stent. Fluid injected into one end of the stent traverses the
stent to whatever openings are provided therein.
Still another known stent set made by Van-Tec of Spencer, Ind.,
under Model No. SI1726, also requires injection of fluid through
one end of the stent for passage within the stent to any available
openings in the stent or an open end of the stent. Since fluid can
only be injected through an end of the stent, fluid infusion cannot
be focused outwardly of the stent at any one location in the stent
if openings are distributed along the length of the stent.
It is thus desirable to provide an infusion stent system which can
be used to infuse fluid at any selected location in a stent and
which also has optimal drainage capability when the stent is left
as an indwelling member.
OBJECTS AND SUMMARY OF THE INVENTION
Among the several objects of the invention may be noted the
provision of a novel infusion stent system, a novel infusion stent
system which permits fluid to be infused into the stent at any
selected location in the stent, a novel infusion stent system which
permits fluid to be infused outwardly of a stent at selected
locations in the stent and also permits maximum drainage of fluid
into the stent when the stent is left as an indwelling member, a
novel infusion stent system which includes an adjustable bypass
member that bypasses openings in the stent to direct outward
infusion of fluid from the stent beyond such bypassed openings, and
a novel method of infusing fluid in the renal cavity.
Other objects and features of the invention will be in part
apparent and in part pointed out hereinafter.
In accordance with the present invention, the infusion stent system
includes a flexible stent member having a main body portion with a
normally curved proximal end portion and a normally looped distal
end portion. Openings can be provided in the wall of the stent
along the entire length thereof including the main body portion and
the proximal and distal end portions.
The system further includes a hollow, flexible guide tube member
open at opposite ends and having an imperforate wall. The stent
member is sized to be drawn over the guide tube member for relative
slidable movement between the stent member and the guide tube
member.
A flexible core member is slidably received in the guide tube
member to stiffen the guide tube member. The core member has an
enlarged portion at one end to limit insertion in the guide tube
member and a terminal portion at the opposite end. The terminal
portion has a reduced cross-section relative to the cross-section
of a main body portion of the core member. A free end of the core
member adjacent the terminal portion has an enlargement that is of
greater magnitude in cross-section than the terminal portion but of
lesser magnitude in cross-section than the main body portion.
The core member can be selectively retracted from the guide tube
member to provide varying degrees of flexibility of the guide tube
member at a proximal end portion thereof.
The infusion stent system further includes a push catheter member
that is also drawn onto the guide tube member for relative slidable
movement between the push catheter member and the guide tube
member.
Location of the infusion stent system in a patient usually begins
with full engagement of the core member in the guide tube member.
The stent member is drawn onto the guide tube member after the core
member has been positioned in the guide tube member.
The flexibility of the core member and the guide tube member are
selected so as to enable the normally curled proximal end portion
and the normally coiled distal end portion of the stent to
substantially straighten when drawn onto the guide tube member and
core member combination.
It should be noted that the guide tube member by itself is too
flexible to straighten the curled proximal end and coiled distal
end portions of the stent member. Thus when the core member is
withdrawn from the guide tube member while the stent member is
disposed on the guide tube member, the curled proximal end portion
and the coiled distal end portion will tend to reform.
Before the stent member is positioned in the renal cavity, the
ureter and the bladder, the guide tube member and core member are
positioned therein. The stent member is urged along the guide tube
member and core member combination into the bladder, the ureter and
the renal cavity by movement of the push catheter along the guide
tube member against the distal end portion of the stent.
Once the stent member has been adequately positioned in the renal
cavity, the ureter and the bladder, the core member can be removed
from the guide tube member, enabling the curved proximal end
portion and the coiled distal end portion of the stent member to
reform in the renal cavity and the bladder. Removal of the core
member opens an infusion channel through the guide tube member into
the stent.
If the proximal end of the guide tube member is located at the
proximal end portion of the stent member, infusion can be directed
into the renal cavity. Since the wall of the guide tube member is
imperforate, openings in the stent member that are bypassed by the
proximal end of the guide tube member are generally not infused
with fluid from the guide tube member.
The guide tube member can be retracted from the proximal end of the
stent member toward the distal end of the stent member to locate
the proximal end of the guide tube member in any selected position
relative to the stent member. Thus, location of the proximal end of
the guide tube member in the main body portion of the stent will
permit infusion of fluid in the ureter as well as the renal cavity.
Location of the proximal end of the guide tube member at the distal
end of the stent will permit infusion to take place through
openings provided along the entire length of the stent.
When the infusion process is completed, the guide tube member can
be removed from the stent member. The stent member can then be left
as an indwelling member and furnishes optimal drainage capability
because of the provision of openings along the entire length of the
stent.
Sutures provided at a distal end of the stent member extend
outwardly of a patient to permit nonsurgical removal of the stent
member when such removal is desired.
The invention accordingly comprises the constructions and method
hereinafter described, the scope of the invention being indicated
in the claims.
DESCRIPTION OF THE DRAWING
In the accompanying drawings,
FIG. 1 is a simplified schematic view of the infusion stent system
in a patient;
FIG. 2 is a simplified perspective view thereof;
FIG. 3 is a side view thereof prior to straightening of the stent
member;
FIG. 4 is a view similar to FIG. 3 after the stent member has been
straightened;
FIG. 5 is a simplified schematic view of a guide tube member and a
core member thereof;
FIG. 6 is an enlarged fragmentary detail, partly shown in section,
of the guide tube member and core member thereof;
FIG. 7 is an enlarged fragmentary sectional view thereof with the
guide tube member and core member positioned in the stent;
FIG. 8 is an enlarged fragmentary sectional view thereof during
infusion, with the core member removed therefrom;
FIG. 9 is an enlarged fragmentary view, partly shown in section, of
the proximal end of the guide tube member and the core member
thereof;
FIG. 10 is a simplified schematic view thereof during initial
installation in the renal cavity, the ureter and the bladder;
FIG. 11 is a view similar to FIG. 10 with the core member partially
retracted from the guide tube member; and,
FIG. 12 is a view similar to FIG. 10 with the core member and guide
tube member entirely removed from the stent member.
Corresponding reference characters indicate corresponding parts
throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
An infusion stent system incorporating one embodiment of the
invention is generally indicated by the reference number 10 in
FIGS. 1 and 2.
The ureteral stent system 10 includes a stent member 12 having a
normally curl-shaped proximal end portion 14, a normally
loop-shaped distal end portion 16 and a elongated main body section
18 intermediate the proximal and distal end portions 14 and 16.
The stent 12, which is formed of a soft, flexible, biocompatible
material such as silicone, has a generally tubular wall 20 with an
internal passageway or lumen 22. A plurality of openings 24 are
provided in the wall 20 at the proximal and distal end portions 14
and 16, and in the main body section 18. The proximal end portion
14 has a tapered or reduced free end 26 which is open at 28. The
distal end portion 16 has a slightly flared free end 30 which is
open at 32. A suture 34 attached to the distal end portion 16
extends from the opening 32.
The system 10 further includes an elongated, hollow, open ended,
flexible guide tube member 36 which the stent member 12 can
slidably accommodate. Referring to FIG. 6, the guide tube member 36
has an internal passageway or lumen 38 and an imperforate wall 40.
The guide tube member 36 is preferably formed of a fluorinated
polymer material such as Teflon, reinforced with stainless steel
wire. Preferably, the stainless steel wire is a flat, rectangular,
Teflon coated wrap.
Referring to FIG. 8, the wire reinforcement 42 can be terminated
before a proximal end 44 of the guide tube member 36 enabling the
proximal end 44 to be slightly reduced as shown in FIG. 9. The
guide tube member also includes an opposite distal end 45.
A flexible, elongated core member 46, preferably formed of
stainless steel, is slidably insertable in the guide tube member 36
and includes a main body portion 48, an enlarged distal end portion
50 and a proximal end portion 52. The enlarged distal end portion
50 is sized to be nonreceivable in the guide tube member 36 to
limit insertion of the core member 46 in the guide tube member
36.
The main body portion 48 has a substantially uniform
cross-sectional magnitude that permits slidable reception in the
guide tube member 36. The proximal end portion 5 of the core member
46 has a reduced terminal section 54 of lesser cross-sectional
magnitude than the main body portion 48. An enlargement 56 formed a
the free end of the proximal end portion 52 joins the terminal
section 54. The enlargement 56 is of greater cross-sectional
magnitude than the terminal section 54 and substantially equivalent
in cross-sectional magnitude to the main body portion 48. The
terminal section 54 is progressively reduced toward the enlargement
56, as for example by reduced steps 58, 60 and 62 or by a
continuous tapering toward the enlargement 56.
A flexible, tubular push-catheter member 64, formed of a suitable
biocompatible polyethylene material, is slidably accommodated on
the guide tube member 36. As shown in FIGS. 7 and 8, a proximal end
66 of the catheter member 64 is sized to butt against the distal
end 16 of the stent member 12. Preferably the combined length of
the stent member 12 and the push-catheter member 64 is less than
the length of the guide tube member 36.
The precise dimensions of the stent system 10 may vary based on the
dimensional characteristics of particular patients. Nevertheless,
to exemplify the magnitudes being dealt with, the outside diameter
of the stent can range from 2.0 to 2.8 mm. The inside diameter of
the stent can range from 1.3 to 1.8 mm. The length of the stent can
range from 12 to 30 cm. The openings in the stent can be provided
approximately every 2 cm. along the main body of the stent and have
a diameter of approximately 1.3 mm. The proximal and distal end
portions of the stent would also contain openings spaced at
approximately 0.8 cm. However such openings would be of a larger
diameter such as 2.2 mm. The sutures 34 can have a 75 cm. trail
from the stent.
The guide tube member 36 can have an outside diameter of
approximately 0.965 mm. and an inside diameter of approximately
0.635 mm. The length of the guide tube member 36 can be
approximately 148 cm.
The core member 46 can have an overall length of approximately
147.5 cm. from the enlarged distal end portion 50 to the
enlargement 56 at the free end of the proximal end portion 52. The
enlargement 50 can be approximately 44.5 mm. long with an outside
diameter of approximately 0.965 mm. The terminal section 54 and
enlargement 56 can be approximately 10.2 cm. long with the
enlargement being approximately 1.22 mm. long and 0.457 mm. in
diameter. The final core diameter before the enlargement 56 is
approximately 0.178 mm.
The push catheter 64 can have an overall length of approximately 70
cm. with an inside diameter of approximately 1.2 mm. and an outside
diameter of approximately 2.9 mm.
In using the stent system 10 for fluid infusion, the core member 46
is inserted in the guide tube member 36 in the manner shown in FIG.
5. Thus, the enlargement 56 at the proximal free end of the core
member 46 is inserted into the distal end 45 of the guide tube
member 36 until the enlarged distal end portion 50 of the core
member 46 abuts the distal end 45 of the guide tube member 36.
The guide tube member 36 and the core member 46 are sized such that
the enlargement 56 at the proximal free end of the core member 46
does not project beyond the proximal end 44 of the guide tube
member 36 when the enlarged distal end portion 50 of the core
member 46 abuts the distal end 45 of the guide tube member 36. The
desired relationship between the enlargement 56 at the proximal
free end of the core member 46 and the proximal end 44 of the guide
tube member 36, when the core member 46 is fully inserted in the
guide tube member 36, is shown in FIG. 9.
The stent member 12 is drawn over the proximal end 44 of the guide
tube member 36 and core member 46 combination. Drawing of the stent
member 12 on the guide tube member 36-core member 46 combination
serves to substantially straighten the normally curl-shaped
proximal end portion 14 and the normally loop-shaped distal end
portion 16 of the stent 12 in the manner shown in FIG. 4.
The push catheter 64 is likewise drawn onto the guide tube member
36 either before or after the stent 12 is in place on the guide
tube member 36 to provide the arrangement shown in FIG. 4.
A luer hub 68 of any suitable known structure such as a Touhy Borst
luer lock is joined to the distal end 45 of the guide tube member
in the manner shown in FIG. 7.
The stent member 12 and the push catheter 64 are slid along the
guide tube member toward the luer hub 68 to expose a predetermined
length of the guide tube member 36 starting from the proximal end
44.
The guide tube member 46 is then positioned in a patient using
known techniques such that the proximal end portion 44 of the guide
tube member 36 is located in the renal cavity 70 (FIG. 10). The
remaining length of the guide tube member 36 extends through the
ureter 72, the bladder 74 and externally of the patient.
It should be noted that the negotiation or positioning of the guide
tube member 36 and core member 46 combination in the renal cavity
70, the ureter 72 and bladder 74 is facilitated by selectively
retracting the core member 46 from the guide tube member 36
predetermined amounts to enhance the flexibility of the proximal
end 44 of the guide tube member 36. Thus, a selective shifting of
the core member 46 within the guide tube member 36 by manipulation
of the enlarged distal portion 50 enables the proximal end portion
of the guide tube member 36 to be softened or stiffened a needed to
aid in negotiating movement of the guide tube member 36 and core
member 46 combination through the ureter.
The reduced terminal section 54 of the core member 46 affords the
guide tube member 36 a greater flexibility at the proximal end
portion 44 than at the distal end portion 45. The flexibility of
the proximal end portion 44 of the guide tube member 36 is further
enhanced by retracting the core member 46 from the proximal end 44
of the guide tube member 36 to further aid in negotiating movement
of the guide tube member 36 through the ureter 72.
After the guide tube member 36 and core member 46 combination have
been adequately located in the renal cavity 70, the ureter 72 and
the bladder 74, the stent member 12 can be positioned in the renal
cavity 70, the ureter 72 and the bladder 74 by the push catheter
64. In accordance with known techniques, the proximal end 66 of the
push catheter 64 is urged against the distal end 16 of the stent
member 12 for movement of the stent member 12 along the guide tube
member 36 to the desired position in a patient. The stent member 12
retains a substantially straightened configuration, such as shown
in FIG. 10, during movement on the guide tube member 36.
When the proximal end portion 14 of the stent member 12 is
adequately located in the renal cavity 70, the core member 46 can
be withdrawn from the guide tube member 36 by maintaining the
proximal end 66 of the push catheter 64 against the distal end 16
of the stent 12 and withdrawing the core member 46. As the core
member 46 is withdrawn, the normally curl-shaped proximal end
portion 14 of the stent member 12 substantially reforms, overcoming
any restraint imposed by the presence of the guide tube member 36
in the stent member 12.
Complete withdrawal of the core member 46 from the guide tube
member 36 enables the normally loop-shaped distal end portion 16 of
the stent 12 to reform in the manner shown in FIG. 12. The
loop-shaped distal end portion 16 of the stent 12 substantially
reforms against any restraints due to the presence of the guide
tube member 36 in the stent member 12.
Thus the guide tube member 36 by itself is insufficient to maintain
the proximal and distal end portions of the stent member 12 in a
straightened condition. The presence of the core member 46 in the
guide tube member 36 provides the necessary restraint to straighten
the proximal and distal end portions 14 and 16 of the stent 12
during positioning in a patient.
During and after installation of the stent 12 in a patient the
sutures 34 are directed alongside the push catheter 64 and extend
outside the patient.
To infuse fluid to the stent 12, a syringe 76 or any other suitable
source of fluid is connected to the luer hub 68. Fluid is thus
injected through the lumen 38 of the guide tube member 36. Since
the wall 40 of the guide tube member 36 is imperforate, any fluid
infused through the distal end 45 of the guide tube member 36 will
exit through the proximal end 44 of the guide tube member 36. Thus
the location of the proximal end 44 of the guide tube member 36 in
the stent 12 determines the point at which fluid will be
distributed outwardly of the stent 12.
For example, if the proximal end 44 of the guide tube member is
located at the proximal end portion 14 of the stent 12 as shown in
FIG. 8, the fluid infused through the guide tube member 36 will
disperse through the openings 24 in the stent that are located
beyond the proximal end 44 of the guide tube member 36.
The openings 24 in the stent member 12 that are bypassed by the
proximal end 44 of the guide tube member 36 generally do not
disperse fluid infused through the guide tube member 36.
The guide tube member 36 thus functions as an infusion channel and
an adjustable bypass member. Accordingly, the guide tube member 36
directs fluid outwardly of the stent through openings beyond any
selected location in the stent.
If it is desired to infuse fluid outwardly of the stent in an area
starting in the ureter, the guide tube member 36 is retracted from
the proximal end 14 of the stent 12. Such retraction is
accomplished by maintaining the proximal end 66 of the push
catheter 64 against the distal end 16 of the stent 12 and
withdrawing the guide tube member 36 a predetermined amount to
position the proximal end 44 of the guide tube member 36 at a
selected location within the stent 12.
The positioning of the proximal end 44 of the guide tube member 36
at a selected relative position within the stent 12 is accomplished
using known monitoring techniques. Since there is sufficient
clearance between the stent 12 and guide tube member 36, the
relative adjustment of the two components is easily
accomplished.
As the guide tube member 36 is retracted from the proximal end 14
toward the distal end 16 of the stent 12, the openings 24 in the
stent 12 that were previously bypassed by the guide tube member 36
become unobstructed for purposes of fluid infusion. Thus, if it is
desired to infuse fluid into the bladder 74 as well as the ureter
72 and the renal cavity 70, the proximal end 44 of the guide tube
member 36 can be located at the distal end 16 of the stent 12.
Since the openings 24 are provided in the stent 12 throughout the
entire length of the stent, any fluid infused at the distal end 16
of the stent 12 would tend to disperse through openings 24 starting
at the distal end 16 of the stent 12.
When fluid infusion is no longer desired in the stent 12 and there
is a need for the stent to perform a drainage function, the guide
tube member 36 can be completely removed from the patient by
engaging the push catheter 64 against the distal end 16 of the
stent while the guide tube member 36 is withdrawn. The stent 12 can
thus be left as an indwelling member for drainage of fluid from the
renal cavity 70 to the bladder 74. The openings 24 provided
throughout the length of the stent 12 including openings 24
provided in the proximal and distal end portions 14 and 16,
optimize the drainage function of the stent 12.
When it is desired to remove the stent 12 from the patient,
withdrawal is easily accomplished by nonsurgical techniques using
the sutures 34 which extend outwardly of the patient.
In some instances it may be desirable to infuse through a stent
member that has no perforations therein. Thus infusion with the
guide tube member will enable fluid to be directed into the stent
member at any selected location.
Some advantages of the present invention evident from the foregoing
description include an infusion stent system that directs fluid to
any selected location within the stent through a guide tube member
that is movable relative to the stent. The guide tube member has a
multiplicity of functions serving as a guide for positioning of the
stent in a patient, an infusion channel for passage of fluid to the
stent and an adjustable bypass member to selectively obstruct
drainage openings in the stent when infusion is required.
Installation of the infusion stent system is advantageously
facilitated by use of a removable core member that can be
selectively located in the guide tube member to selectively soften
and stiffen the proximal tip of the guide tube member and aid in
negotiation of the ureter during positioning of the stent. A
further advantage of the infusion stent system is that the stent
can function as an indwelling drainage member after infusion is
completed, and will provide optimal drainage because of the
presence of openings along the entire length of the stent.
In view of the above, it will be seen that the several objects of
the present invention are achieved and other advantageous results
attained.
As various changes can be made in the above constructions and
method without departing from the scope of the invention, it is
intended that all matter contained in the above description or
shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
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